In a computer visual system, camera calibration is a process of obtaining geometric and optical features inside the camera, namely, internal parameters, and obtaining the three-dimensional location relation between the camera coordinate system and the space coordinate system, namely, approximation of external parameters.
No matter what camera calibration method is adopted, obtaining clear images automatically is a foundation of successful calibration. If the images are not clear, the calibration result is deteriorated.
In the process of developing the present invention, the inventor finds that the prior art does not define how to obtain clear images automatically. The image processing in the prior art requires the photographer to take photos from different perspectives, which brings inconvenience to the person who holds the image and to the photographer. In most circumstances, an image is obtained through cooperation of two persons. In practical experiment, using unclear images calibrating a camera leads to great errors of the calibration results or even failure of obtaining the calibration results. In the prior art, the photographer has to take multiple photos and select a clear and qualified image among them for detecting feature information, and the camera is unable to select a proper clear image automatically.